Chapter 1: Living Things Aim: What is the difference between living and nonliving things?

Characteristics of Living Things Organized Grow and develop Reproduce Respond to stimuli Maintain certain internal conditions Use energy Things that have ALL of these characteristics are called organisms

Organized Made up of small units called cells Cells contain structures with specialized functions Some organisms are unicellular (one cell only) Some are multicellular (two or more cells) Each cell contains heredity material and has a structure Growth and Development Unicellular organisms grow as the cell increases Multicellular organisms grow as their cells increase in number Changes that occur in an organism during its lifetime are called development

Reproduce Reproduction is the process by which one organism makes one or more new organisms All organisms reproduce differently Respond to Stimuli All living things respond to changes in their environment Changes can be internal or external Internal stimuli: ex: feeling hungry or thirsty External stimuli: ex: light and temperature Homeostasis An organisms ability to maintain steady internal conditions when outside conditions change

Ensures that cells can function Energy Cells use energy to transport substances, make new cells, and perform chemical reactions Everything an organism does requires energy Energy comes from the sun directly or indirectly

Nonliving Things Don’t have all of these characteristics Don’t need things in order to survive Examples: Water Air Rocks Clouds

Aim: What are the basic needs of all living things? Place to live Some need a hot environment Some need a cold environment Some live in the ocean Few live on the bottom of the ocean Organisms surroundings must provide for all of its needs

2. Raw Materials all living things need water Most organisms made up of 50 % H2O Humans made up of 60-70% H2O Need proteins, fats and sugars

Aim: How do we classify living things?

Classification Early classifications included grouping plants depending on how they were used and animals on human traits, such as courageous Aristotle classified living things by how they looked Example: Animal categories included hair or no hair, four legs or two legs

Modern classification Carolus Linnaeus came up with a new system of classification based on the structure of the organism Modern classification Includes Linnaeus’ system Similarities of internal and external factors study fossils, hereditary information and early stages of development Scientists use all of this information to find and organisms phylogeny

Today’s Classification System Organisms are grouped into six kingdoms Kingdom is the first and largest category Organisms are placed into these kingdoms based on various characteristics Smallest classification is a species Organisms that belong to the same species can mate and reproduce

Aim: How do scientists name organisms?

Binomial Nomenclature Two-word naming system used by Linnaeus Used by modern scientists First word identifies the genus of the species Second words tells you something about the organism-what it looks like, lives or who discovered it Examples: Red Maple Tree=Acer Rubrum

Using Scientific Names Used for four reasons: Help avoid mistakes Organisms with similar evolutionary history are classified together in the same genus Give descriptive information Allows information about organisms to be organized easily and efficiently

Aim: How do you use a dichotomus key?

Tools for Identifying Organisms Field guides Have descriptions and illustrations of organisms Information about where they live Can identify species from around the world

Dichotomous keys Detailed list identifying characteristics that includes scientific names Arranged in steps Can identify and name species